UNIT_FLAG_UNKNOWN_1                  =  0x00000001, -- 1            1
UNIT_FLAG_NOT_ATTACKABLE_2           =  0x00000002, -- 2            2  client won't let you attack them
UNIT_FLAG_LOCK_PLAYER                =  0x00000004, -- 3            4  ? does nothing to client (probably wrong) - only taxi code checks this
UNIT_FLAG_PLAYER_CONTROLLED          =  0x00000008, -- 4            8  makes players and NPCs attackable / not attackable
UNIT_FLAG_UNKNOWN_5                  =  0x00000010, -- 5           16  ? some NPCs have this
UNIT_FLAG_UNKNOWN_6                  =  0x00000020, -- 6           32
UNIT_FLAG_PLUS_MOB                   =  0x00000040, -- 7           64  ? some NPCs have this (Rare/Elite/Boss?)
UNIT_FLAG_UNKNOWN_8                  =  0x00000080, -- 8          128  ? can change attackable status 
UNIT_FLAG_NOT_ATTACKABLE_9           =  0x00000100, -- 9          256  changes attackable status
UNIT_FLAG_UNKNOWN_10                 =  0x00000200, -- 10         512  ? some NPCs have this
UNIT_FLAG_LOOTING                    =  0x00000400, -- 11        1024
UNIT_FLAG_SELF_RES                   =  0x00000800, -- 12        2048  ? some NPCs have this
UNIT_FLAG_PVP                        =  0x00001000, -- 13        4096  sets PvP flag
UNIT_FLAG_SILENCED                   =  0x00002000, -- 14        8192
UNIT_FLAG_DEAD                       =  0x00004000, -- 15       16384  used for special "dead" NPCs like Withered Corpses
UNIT_FLAG_UNKNOWN_16                 =  0x00008000, -- 16       32768  ? some NPCs have this
UNIT_FLAG_ALIVE                      =  0x00010000, -- 17       65536  ?
UNIT_FLAG_PACIFIED                   =  0x00020000, -- 18      131072
UNIT_FLAG_STUNNED                    =  0x00040000, -- 19      262144
UNIT_FLAG_COMBAT                     =  0x00080000, -- 20      524288  sets combat flag
UNIT_FLAG_MOUNTED_TAXI               =  0x00100000, -- 21     1048576  mounted on a taxi
UNIT_FLAG_DISARMED                   =  0x00200000, -- 22     2097152
UNIT_FLAG_CONFUSED                   =  0x00400000, -- 23     4194304
UNIT_FLAG_FLEEING                    =  0x00800000, -- 24     8388608  fear
UNIT_FLAG_PLAYER_CONTROLLED_CREATURE = 0x01000000, -- 25    16777216
UNIT_FLAG_NOT_SELECTABLE             = 0x02000000, -- 26    33554432  cannot select the unit
UNIT_FLAG_SKINNABLE                  =  0x04000000, -- 27    67108864
UNIT_FLAG_UNKNOWN_28                 =  0x08000000, -- 28   134217728  ? was MAKE_CHAR_UNTOUCHABLE (probably wrong), nothing ever set it
UNIT_FLAG_UNKNOWN_29                 =  0x10000000, -- 29   268435456
UNIT_FLAG_FEIGN_DEATH                =  0x20000000, -- 30   536870912
UNIT_FLAG_UNKNOWN_31                 =  0x40000000, -- 31  1073741824  ? was WEAPON_OFF and being used for disarm
UNIT_FLAG_UNKNOWN_32                 =  0x80000000,